1. Field of the Invention
This invention relates to a fuel injection valve for an internal combustion engine, and more particularly to a vortex nozzle for use in a fuel injection valve for shortening the injection distance without hindering the atomization of the fuel.
2. Description of the Prior Art
The prior art teaches both inwardly and outwardly opening, vortex type fuel injection valves for gasoline, Diesel and other types of internal combustion engines. Such valves suffer from the disadvantage, however, that some fuel remains in the space between the needle valve seat and its injection opening after the completion of each injection cycle, and such residual fuel hinders the swirling flow of fuel in the subsequent injection cycle. Thus, the fuel is not completely atomized, but instead is injected in a liquid form with a large force to impinge on and cling to the walls of the combustion chamber. This in turn prevents or retards the complete combustion of the fuel. In addition, when a vortex chamber is provided above the valve seat, as disclosed in Japanese Patent Publication 6556/1951 and Japanese Utility Model Publication 9705/1956, large size droplets or particles of fuel are produced in the initial stages of injection. On the other hand, if the distance between the vortex chamber and the valve seat is increased, then a large resistance loss occurs, which inhibits the desired fuel swirling effect and results in excessive exhaust gas pollutants.